Table 1. Number of injuries versus subject or injury characteristics.

Characteristics	Grade 1–4		Grade 5–8		Grade 9–12		Total		p-value
	n	%	n	%	n	%	n	%
Gender
Boys	826	78.7	230	58.8	140	67.6	1196	72.6	< 0.001
Girls	223	21.3	161	41.2	67	32.4	451	27.4
Location of injury
Playground	328	39.5	140	46.7	109	62.3	577	44.2	< 0.001
Classroom	331	39.8	112	37.3	53	30.3	496	38.0
Hallway	172	20.7	48	16.0	13	7.4	233	17.8
Time of injury
In class	336	38.4	120	36	53	29.3	509	36.7	< 0.001
Break	349	39.9	106	31.8	35	19.3	490	35.3
Physical education period	189	21.6	107	32.1	93	51.4	389	28.0
Types of injury
Abrasion or scrape	568	62.5	170	54.1	93	55.0	831	59.7	< 0.001
Cut or laceration	260	28.6	92	29.3	27	15.0	379	27.2	0.001
Pain or tenderness	81	8.9	52	16.6	49	29.0	182	13.1	< 0.001
Contributing factors
Fall	407	52.2	117	47.2	60	46.2	584	50.4	0.425
Collision with an object	233	29.9	83	33.5	40	30.8	356	30.7
Collision with a person	140	17.9	48	19.4	30	23.1	218	18.8
Severity
Yes	164	15.9	60	15.7	38	18.6	262	16.2	0.590
No	870	84.1	323	84.3	166	81.4	1359	83.8
Equipment involvement
Yes	250	25.3	112	29.9	40	19.7	402	25.7	0.024
No	739	74.4	262	70.1	163	80.3	1164	74.3